- do the quandaries described in the previous
question ever occur? Choose a group of organ-
isms that interests you, find recent phylogenetic
studies of this group, and see whether such
problems have been encountered. (you can do
this using key words, such as “phylogeny” and
“[taxon name],” e.g., “[deer],” in any of several
literature-search engines that your instructor can
suggest.) - Phylogenetic reconstruction can be obscured
by homoplasy, rapid diversification, and intro-
gression. How can researchers identify those
potential complications and ensure that their
phylogenetic trees are robust to them? - Suppose species 1, 2, and 3 are endemic to a
group of islands (such as the galápagos) and are
all descended from species 4 on the mainland
(which will serve as an outgroup; its large popu-
lation size means that no new mutations have
become fixed in its population in the time since
the islands were colonized). you sequence a
gene and find ten nucleotide sites that differ
among the four species (among many other loci
that do not vary). The nucleotide bases at these
sites are:
Species 1: gCTgATgAgT
Species 2: ATCAATgAgT
Species 3: gTTgCAACgT
Species 4: gTCAATgACA
Estimate the phylogeny of these taxa by plot-
ting the changes on each of the three possible
unrooted trees and determining which tree
requires the fewest evolutionary changes.16_EVOL4E_CH16.indd 429 3/22/17 1:34 PM